250 



INDEX 



'' Nurture," 131, 171, 174, 176 

 Nutritive chains, 48 



O 



Organic progress, 95 



Organisms, correlation of, 45 ; 

 interdependence of, for con- 

 tinuance of species, 51 



" Origin of Species," 98 



Osborn.H. F.,119, 129, 169, 206 



Pairing of similar pure-bred 



forms, 145 

 Pahidma, 25 



Pangenesis, Darwin's idea of , 163 

 Parasites, life-histories of, 66 

 Parasitism, 93 



Parthenogenesis, artificial, 121 

 Particulate inheritance, 146 

 Pearson, Prof. Karl, 33, 36, 130, 



143, 203, 231 

 Peckham, Prof, and Mrs., 209 

 Peridinidse, 50 

 Phenaoodxis, 24 

 Pigeons, variation in, 185 

 Planorbis, 25 

 P!asticity, individual, 121; of 



organism, 173 

 Plate, 192 

 Play, 125 

 Poulton, Prof. E. B., 72, 83, 122, 



186, 197, 199 

 Problems of the Naturalist, 6 

 Przribram, Dr., 138 

 Punnett on Mendelism, 136, 151 



Quetelet, 102 



B 

 Rats, brown versus black, 74, 84 

 Becapitulation theory, 26 

 Becessive characters, 149 

 Begression, 142 



Reversed selection in human 



society, 222 

 Reversion, 147 

 Romanes, 35, 161, 211 

 Rudimentary organs, 23 

 Russell, E. S., 188, 202 



S 



Saleeby, 81, 230 



Saunders, 199 



Scientific mood, ideals of, 31 ; 

 characteristics of, 32 



Seeds, scattering of, 53 



Selection and stimulus, 168; or- 

 ganic and social, 181-212; 

 periodic, 201 ; sexual, 207 ; in 

 human society, 213 ; social 

 and natural, 220. iSee Natural 

 Selection 



Semon, experiments with aca- 

 cias 171 



Silvestri, 60 



Specialism, Darwin and, 31 



Spencer, 88, 159, 163. 170, 183, 

 217 ; and Darwin, 71 



Sprengel, Christian Conrad, 52 



Squirrels and wood-pigeons, 62 



Staples-Browne, 147 



Statistical study, 139 



Stevenson, R. L., 77 



Strasburger, 134 



Struggle for existence, 1 1, 63-94 ; 

 between fellows, 73 ; between 

 foes, 74 ; with fate, 76 ; among 

 plants, 76; reasons for, 80; 

 results of, 83 ; Darwin's con- 

 ception of, 86 ; conception of 

 applied to human life, 92 



T 



Tennyson, 12, 70 

 Termites, 59 

 Tierra del Fuego, 5 

 Tower, Prof., 115 

 Transmissibility of acquired cha- 

 racters, 170 



